This invention relates to switching arrangements and, more particularly, to switching arrangements operable in response to particular frequencies of sound.
There has long been a need for detectors capable of sensing particular sounds (or more broadly, vibration frequencies). Such detectors have been used for a great number of purposes including among other things vibrationally actuated devices for sensing intruders, acoustically actuated switches, sound controlled toys, and sound actuated lights.
Although many such detectors exist, no economically feasible device exists for use with non-metallic lamp fixtures. Moreover, the call for more advanced automation features has exposed problems in automatic control arrangements. For example, the automatic detectors used with sound actuated lights have been found to respond to a great many extraneous vibrations which, in effect, render the devices useless. Many such devices respond to rumblings caused by heavy vehicles, to footsteps, room sounds, and to any number of other local sounds.